State of art communication systems such as the method and device disclosed in American patent application no.: US 2005/0089183, which hereby is incorporated in the below specification by reference, generally utilise an inductive link operating at a very low data rate so as to avoid large power requirements. The method and device disclosed in the patent application prioritizes between types of data packages so as to, for example, enable a remote control unit to interrupt communication between a set of hearing aids.
Inductive links, which in this context are to be construed as magnetic links, are generally used for short-range wireless communication between a set of hearing aids, or between a hearing aid and an accessory element such as a Bluetooth gateway, remote control or the like. However, because of the limited power available to a hearing aid due to the small battery, it is desirable to have an antenna, which is as power-efficient as possible. That is an antenna, which generates as much magnetic field as possible with the lowest current consumption.
The limiting factor is a basic trade off between power efficiency and antenna bandwidth. An antenna designed for low loss results in antennas having small bandwidth and consequently an insufficient data transfer rate. On the other hand, an antenna designed for a small bandwidth results in envelopes of transmitted signals not changing fast enough to carry the desired modulation, i.e. a receiver cannot register that a bit has been sent before a subsequent bit is to be transmitted.